Devices are known in which matrices of organic light emitting diodes (OLEDs) are controlled by control circuits that have transistors. In such devices, anodes of OLEDs can be coupled to a source of a transistor which supplies power to the OLED, and cathodes of the OLEDs may be coupled to a negative potential.
To adjust the total brightness emitted by the matrix of the OLED pixels and to obtain a dimming effect, provision has been made for varying this negative potential to which the cathodes of the OLEDs are coupled.
This being the case, OLEDs of different colors can react differently to this voltage variation at their cathodes. Due to this fact, variations of the cathode voltage can be accompanied by a loss of quality of the displayed colors.
Therefore, further development in the field of OLEDs and control circuits therefor are desirable.